Can one pray istikhaarah with just one rak‘ah?

What appears to be the case is that the Sunnah of istikhaarah
cannot be done by praying just one rak‘ah, because of the report narrated by
Jaabir ibn ‘Abdullah (may Allah be pleased with him) who said: The Messenger
of Allaah (peace and blessings of Allaah be upon him) used to teach his
companions to make istikhaarah in all things, just as he used to teach them
soorahs from the Qur’aan. He said: ‘If any one of you is concerned about a
decision he has to make, then let him pray two rak‘ahs of non-obligatory
prayer…

Narrated by al-Bukhaari, 1166. 

Al-Bujayrami (may Allah have mercy on him) said: The words of
the Prophet (blessings and peace of Allah be upon him) referring to two
rak‘ahs of istikhaarah indicate that it cannot be done with just one rak‘ah.

End quote from Tuhfat al-Habeeb ‘ala Sharh al-Khateeb,
1/428 

Al-‘Ayni (may Allah have mercy on him) said: The evidence
indicates that the Sunnah in istikhaarah is to pray two rak‘ahs, therefore
one rak‘ah is not acceptable for istikhaarah.

End quote from ‘Umdat al-Qaari’ Sharh Saheeh al-Bukhaari,
11/385 

Ash-Shawkaani (may Allah have mercy on him) said: The words
“let him pray two rak‘ahs” indicate that the Sunnah in istikhaarah is to
make it two rak‘ahs, so one rak ‘ah is not acceptable.

End quote from Nayl al-Awtaar, 3/88.